Bird migrations leading indicators of climate change

Mockingbirds, others moving north as Ohio warms

Aug. 26, 2013

Four baby mockingbirds rest in their nest in a fir tree in Knox County. Mockingbirds, native to the South, are becoming increasingly visible in many parts of Ohio as the climate warms. / Todd Hill/Telegraph-Forum

Written by

Todd Hill

CentralOhio.com

Ohio’s changing climate

To show how Ohio’s climate and environment are changing, the Media Network of Central Ohio sought concrete examples showing the state’s environment isn’t what it used to be, regardless of the cause. During the course of a week, we will present several of these examples, but we know we can’t hit them all. If you have a story about the environment to share, tell us via our Facebook page. All the stories from the series will be posted to NewarkAdvocate.com/climate as they appear online or in print.

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Whenever we experience a prolonged heat wave in the summer or a winter cold spell, we’re reminded of how narrow our range of comfortable weather really is.

Of course, humans have a much greater range of options available to us for coping with temperature extremes, beginning with living indoors. Animals have no such luxury, so they are being forced to adapt to today’s era of climate change by taking more drastic measures, such as pulling up roots and finding new homes.

“Anything that can move great distances over a shorter time has a great advantage,” said Warren Uxley, a naturalist with the Crawford County Park District.

Birds are considered some of the most reliable bio-indicators of phenomena such as climate change for that reason. Naturalists across Ohio, particularly those with an interest in birding, have observed and documented a variety of species new to the state, while other species appear to have flown away.

“Birds are shifting northward within the state on a gradual basis that’s consistent with the idea of the climate warming. And birds are staying here during the winter that formerly didn’t,” said Kenn Kaufman, a member of the board of directors at the Black Swamp Bird Observatory in Ottawa County.

“So far it’s the short-distance migrants, like killdeer, eastern phoebe and American woodcock. With the long-distance migrants — and we have some that travel to South America — there has not been a discernible change in their migration.”

Birders have noted a variety of specific species ranges that are no longer what they used to be across Ohio.

“The magic line between black-capped chickadees to the north and Carolina chickadees to the south used to be U.S. 30, and now we have Carolinas north of 30,” said Cheryl Harner, president of the Greater Mohican Audubon Society.

She also noted that the northern mockingbird is starting to make significant inroads into Ohio. The species is ingrained in southern culture, from the 19th-century folk song “Listen to the Mocking Bird,” popular during the Civil War, to Harper Lee’s Pulitzer Prize-winning 1960 novel “To Kill a Mockingbird,” set in Alabama.

Mockingbirds have been widely reported in Columbus for the past few years and are just now moving into the Mansfield area, according to eBird, a website that documents the presence or absence of species, as well as bird abundance, through checklist data.

“We’re seeing more black vultures than in the past. That’s a southern bird,” Uxley said. “And turkey vultures have been found in northern Michigan. That certainly wasn’t the case 15 years ago.”

Kaufman has seen a variety of changes in bird behavior in the Lake Erie marshlands, one of the more active migration corridors in the United States.

“Tundra swans are now staying the winter in Ottawa (National Wildlife Refuge) and Magee Marsh in the hundreds, even low thousands. Before, they migrated to Chesapeake Bay. Sandhill crane numbers here are increasing. They’re staying later and arriving earlier in the spring,” he said.

“Golden-winged warblers used to nest in Toledo. That was on the southern end of their range, and now it’s moved northward into Michigan.”

Even bird species that have been calling Ohio home for years, or at least part of the year, are changing their behavior, particularly in regard to migration.

“There’s an advantage to coming back as early as they can to establish territory,” Kaufman said, “but it’s a process of trial and error. If they arrive too early, they run the risk of freezing to death.”

Online networks, such as eBird, are playing a key role in monitoring how birds are responding to climate change.

“It’s a volunteer thing. There are millions of entries from across North America on various species,” Uxley said. “You can graph the trends to see what’s happening. There’s so much data that you can correlate it.”

Harner lamented the absence of beetle counts and frog societies but noted the importance of winter bird counts in detailing what’s happening with Ohio’s bird populations.

There are 75 winter bird counts organized in the state — birds are easier to spot in trees without leaves — covering 73 of Ohio’s 88 counties, according to the Ohio Ornithological Society. Holmes County is home to five such counts, more than any other county, as the Amish living there are heavily involved in birding. Richland, Geauga and Hamilton counties are each home to four winter bird counts.

Harner pointed out that factors other than climate change might be influencing avian behavior.

“Bird feeding is new as well. Fifty years ago, no one fed birds. Now goldfinches will stay in close,” she said.

“Birds will probably not die if you stop feeding. They’ll disperse or find a different feeder. Ice storms are what have a terrible impact. That’s when you’re making a life-or-death decision. It doesn’t take very long for a little bird to die.”